Does parenthood equal adulthood?

Based on numerous conversations I've had with my own mother recently, I am beginning to conclude that parenthood does not equal adulthood, neither my own nor my mother's. My relationship with my mother has changed in recent years; she had begun to see me as an adult, and in several instances, I've felt more like the parent than the child. Recently though my mother has made several pointed comments that lead me to conclude that since I have become pregnant she sees me more as a child than an adult. I had thought that my impending parenthood would force her to see me as an adult--not so! She has begun treating me like a teenager again, constantly questioning my decisions, voicing concern about our plans, and repeatedly questioning C's abilities. I expected all but the last. To be quite honest, my mother's love for C has always disturbed me somewhat. From the moment I introduced them, she thought he was perfect. He was the perfect boyfriend who became the son-in-law who could do no wrong. She repeatedly compared him to my sister's husband, always finding C to be exemplary in everything while expressing disgust with my brother-in-law (a bit odd, I know).

But since I've been pregnant, my mother has vocally questioned everyone of C's personality traits, from his relatively laid back style to his anal-ness about certain things. She even suggested I have someone else with me in the delivery room to ensure I wouldn't be alone when C "freaks out." Suddenly the one thing I thought she felt I did completely right--picking out the "perfect mate/son-in-law"--she is unhappy with. Her need to question my decisions and to question C has left me feeling as though I'm suddenly 14 all over again--incapable of doing anything to please her. I've been pondering the ultimately unanswerable questions: will my mother ever see me as an adult? And why does it bother me so much that she still sees me as a child? And how do I avoid treating my child in this way?